Java example source code file (SecuritySupport.java)

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Java - Java tags/keywords

arraylist, classloader, enumeration, inputstream, ioexception, list, net, network, object, privilegedaction, privilegedactionexception, privilegedexceptionaction, security, securityexception, securitysupport, string, url, util

The SecuritySupport.java Java example source code

/*
 * Copyright (c) 2002, 2005, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */

package javax.activation;

import java.security.*;
import java.net.*;
import java.io.*;
import java.util.*;

/**
 * Security related methods that only work on J2SE 1.2 and newer.
 *
 * @since 1.6
 */
class SecuritySupport {

    private SecuritySupport() {
        // private constructor, can't create an instance
    }

    public static ClassLoader getContextClassLoader() {
        return (ClassLoader)
                AccessController.doPrivileged(new PrivilegedAction() {
            public Object run() {
                ClassLoader cl = null;
                try {
                    cl = Thread.currentThread().getContextClassLoader();
                } catch (SecurityException ex) { }
                return cl;
            }
        });
    }

    public static InputStream getResourceAsStream(final Class c,
                                final String name) throws IOException {
        try {
            return (InputStream)
                AccessController.doPrivileged(new PrivilegedExceptionAction() {
                    public Object run() throws IOException {
                        return c.getResourceAsStream(name);
                    }
                });
        } catch (PrivilegedActionException e) {
            throw (IOException)e.getException();
        }
    }

    public static URL[] getResources(final ClassLoader cl, final String name) {
        return (URL[])
                AccessController.doPrivileged(new PrivilegedAction() {
            public Object run() {
                URL[] ret = null;
                try {
                    List v = new ArrayList();
                    Enumeration e = cl.getResources(name);
                    while (e != null && e.hasMoreElements()) {
                        URL url = (URL)e.nextElement();
                        if (url != null)
                            v.add(url);
                    }
                    if (v.size() > 0) {
                        ret = new URL[v.size()];
                        ret = (URL[])v.toArray(ret);
                    }
                } catch (IOException ioex) {
                } catch (SecurityException ex) { }
                return ret;
            }
        });
    }

    public static URL[] getSystemResources(final String name) {
        return (URL[])
                AccessController.doPrivileged(new PrivilegedAction() {
            public Object run() {
                URL[] ret = null;
                try {
                    List v = new ArrayList();
                    Enumeration e = ClassLoader.getSystemResources(name);
                    while (e != null && e.hasMoreElements()) {
                        URL url = (URL)e.nextElement();
                        if (url != null)
                            v.add(url);
                    }
                    if (v.size() > 0) {
                        ret = new URL[v.size()];
                        ret = (URL[])v.toArray(ret);
                    }
                } catch (IOException ioex) {
                } catch (SecurityException ex) { }
                return ret;
            }
        });
    }

    public static InputStream openStream(final URL url) throws IOException {
        try {
            return (InputStream)
                AccessController.doPrivileged(new PrivilegedExceptionAction() {
                    public Object run() throws IOException {
                        return url.openStream();
                    }
                });
        } catch (PrivilegedActionException e) {
            throw (IOException)e.getException();
        }
    }
}